Location of light-repressible, small GTP-binding protein of the YPT/rab family in the growing zone of etiolated pea stems.

Nagano, Yukio; Okada, Yasuo; Narita, Hiroshi; Asaka, Yukiko; Sasaki, Yukiko

doi:10.1073/pnas.92.14.6314

Cited by 40 publications

(49 citation statements)

References 25 publications

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“…Rab11 activity has also been implicated to be important for the secretion of cell wall modifying enzymes in ripening tomato (Lycopersicon esculentum) (Zainal et al, 1996;Lu et al, 2001). Other Rab11 homologs have been shown to be involved in light signal transduction and the biosynthesis of brassinosteroid (Yoshida et al, 1993;Nagano et al, 1995;Kang et al, 2001). Therefore, each plant Rab11 homolog or subsets of closely related homologs may have a highly specialized function that cannot be derived by analogy with their counterparts from other organisms but needs to be experimentally determined.…”

Section: Introductionmentioning

confidence: 99%

Rab11 GTPase-Regulated Membrane Trafficking Is Crucial for Tip-Focused Pollen Tube Growth in Tobacco

et al. 2005

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Pollen tube growth is a polarized growth process whereby the tip-growing tubes elongate within the female reproductive tissues to deliver sperm cells to the ovules for fertilization. Efficient and regulated membrane trafficking activity incorporates membrane and deposits cell wall molecules at the tube apex and is believed to underlie rapid and focused growth at the pollen tube tip. Rab GTPases, key regulators of membrane trafficking, are candidates for important roles in regulating pollen tube growth. We show that a green fluorescent protein–tagged Nicotiana tabacum pollen-expressed Rab11b is localized predominantly to an inverted cone-shaped region in the pollen tube tip that is almost exclusively occupied by transport vesicles. Altering Rab11 activity by expressing either a constitutive active or a dominant negative variant of Rab11b in pollen resulted in reduced tube growth rate, meandering pollen tubes, and reduced male fertility. These mutant GTPases also inhibited targeting of exocytic and recycled vesicles to the pollen tube inverted cone region and compromised the delivery of secretory and cell wall proteins to the extracellular matrix. Properly regulated Rab11 GTPase activity is therefore essential for tip-focused membrane trafficking and growth at the pollen tube apex and is pivotal to reproductive success.

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Section: Introductionmentioning

confidence: 99%

Rab11 GTPase-Regulated Membrane Trafficking Is Crucial for Tip-Focused Pollen Tube Growth in Tobacco

et al. 2005

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“…In pea, mRNA levels of small Ras-like G proteins, including Pra2 and Pra3, are reversibly regulated by red and far-red light (25). Pra2 has been especially well characterized (26,27). A recent study found that Pra2 regulates the cytochrome 450 that catalyzes C-2 hydroxylation in brassinosteroid biosynthesis, and this catalytic activation is down-regulated by light (28).…”

Section: Introductionmentioning

confidence: 99%

Arabidopsis nucleoside diphosphate kinase-2 as a plant GTPase activating protein

Shen¹,

Han²,

Kim³

et al. 2008

BMB Reports

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Nucleoside diphosphate kinase (NDPK) is involved in multiple signaling pathways in mammalian systems, including G-protein signaling. Arabidopsis NDPK2, like its mammalian counterparts, is multifunctional despite its initial discovery phytochrome-interacting protein. This similarity raises the possibility that NDPK2 may play a role in G-protein signaling in plants. In the present study, we explore the potential relationship between NDPK2 and the small G proteins, Pra2 and Pra3, as well as the heterotrimeric G protein, GPA1. We report a physical interaction between NDPK2 and these small G proteins, and demonstrate that NDPK2 can stimulate their GTPase activities. Our results suggest that NDPK2 acts as a GTPase-activating protein for small G proteins in plants. We propose that NDPK2 might be a missing link between the phytochromemediated light signaling and G protein-mediated signaling.[BMB reports 2008; 41(9): 645-650]

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“…In plants, these subclasses are based almost entirely on sequence comparisons, and whether they represent functional groups is not clear. In the absence of effective in vivo trafficking assays, information on plant Rab GTPase function has been derived from complementation and expression studies in yeast (Palme et al, 1992;Bednarek et al, 1994;Ueda et al, 2000), immunolocalization data (Ueda et al, 1996), and expression studies (Terryn et al, 1993;Nagano et al, 1995;Moore et al, 1997). Transgenic approaches suggest that disrupting Rab function produces various developmental and cellular anomalies, but they have not identified the in vivo trafficking roles of any plant Rab GTPase (Cheon et al, 1993;Bischoff et al, 1999).…”

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confidence: 99%

A Rab1 GTPase Is Required for Transport between the Endoplasmic Reticulum and Golgi Apparatus and for Normal Golgi Movement in Plants

et al. 2000

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We describe a green fluorescent protein (GFP)-based assay for investigating membrane traffic on the secretory pathway in plants. Expression of At Rab1b(N121I), predicted to be a dominant inhibitory mutant of the Arabidopsis Rab GTPase At Rab1b, resulted in accumulation of a secreted GFP marker in an intracellular reticulate compartment reminiscent of the endoplasmic reticulum. This accumulation was alleviated by coexpressing wild-type At Rab1b but not At Rab8c. When a Golgi-targeted and N -glycosylated variant of GFP was coexpressed with At Rab1b(N121I), the variant also accumulated in a reticulate network and an endoglycosidase H-sensitive population appeared. Unexpectedly, expression of At Rab1b(N121I), but not of the wild-type At Rab1b, resulted in a reduction or cessation of vectorial Golgi movement, an effect that was reversed by coexpression of the wild type. We conclude that At Rab1b function is required for transport from the endoplasmic reticulum to the Golgi apparatus and suggest that this process may be coupled to the control of Golgi movement. INTRODUCTIONThe structure and biosynthetic activities of the endoplasmic reticulum (ER) and Golgi apparatus in higher plants are well described, but the mechanisms that promote and regulate membrane traffic between these compartments are not well understood (reviewed in Robinson and Kristen, 1982;Staehelin and Moore, 1995;Dupree and Sherrier, 1998;Vitale and Denecke, 1999). The Golgi apparatus in higher plants exists as a large number of independent Golgi stacks distributed throughout the cytoplasm. Each Golgi stack typically comprises five to eight flattened cisternae, whose protein and polysaccharide composition may vary in a cis to trans direction across the stack (Zhang and Staehelin, 1992; Wee et al., 1998;Nebenführ et al., 1999). Analysis of tobacco cells in which the Golgi stacks were labeled with green fluorescent protein (GFP) revealed that each stack can travel as much as 2 to 4 m sec Ϫ 1 on an actin network that is coextensive with the dynamic ER network (Boevink et al., 1998;Nebenführ et al., 1999). Consequently, despite the dynamic organization of both the ER and Golgi, both organelles remain in close association. The movement of individual Golgi stacks appears to alternate between two modes: a directed vectorial mode, probably dependent on myosin motors, and a nonvectorial mode involving apparently random oscillations reminiscent of Brownian motion at particular points in the cytoplasm (Nebenführ et al., 1999). Video microscopy of GFP-labeled Golgi stacks in cultured tobacco cells suggests that the control of Golgi movement is devolved to the individual stacks because adjacent stacks can enter independently into phases of vectorial movement, and a stack undergoing vectorial movement can travel past another that is exhibiting the nondirected oscillatory type of motion (Nebenführ et al., 1999).In contrast, the mammalian Golgi apparatus in general forms a single interconnected cluster of membranes at the microtubule organizing center. ER-derived COP...

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Location of light-repressible, small GTP-binding protein of the YPT/rab family in the growing zone of etiolated pea stems.

Cited by 40 publications

References 25 publications

Rab11 GTPase-Regulated Membrane Trafficking Is Crucial for Tip-Focused Pollen Tube Growth in Tobacco

Rab11 GTPase-Regulated Membrane Trafficking Is Crucial for Tip-Focused Pollen Tube Growth in Tobacco

Arabidopsis nucleoside diphosphate kinase-2 as a plant GTPase activating protein

A Rab1 GTPase Is Required for Transport between the Endoplasmic Reticulum and Golgi Apparatus and for Normal Golgi Movement in Plants

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